Field of the Invention
The disclosure generally relates to an impedance circuit, and more specifically, to an impedance circuit and poly-resistors therein.
Description of the Related Art
Poly-resistors are characterized by their sheet resistance values. In order to reduce the chip size, the poly-resistors with high sheet resistance values are often used and fabricated in a small area, and they are extensively used in a variety of integrated circuits.
However, the depletion effect is a phenomenon in which there is unwanted variation in the threshold voltage of devices using poly-silicon as a gate material, leading to unpredictable behavior on the part of electronic circuits. It results in serious non-linearity of the poly-resistors. Accordingly, there is a need for a novel solution for suppressing the non-ideal depletion effect in poly-resistors.